This move helps White's attack, since the king goes directly into the fire.
9. d4e5  9... d8c7  10. c1f4 The fourth most popular move. Nepomniachtchi, as do all elite players, has his own views on opening theory. 10... g8e7  11. a2a4 A logical move, preparing the development of the knight on a3, but it's not clear how White will react when Black plays a7-a6. It seems to me that both players confused the move order in the opening, which is not surprising; after all, this is a blitz game.